The present invention concerns high-strength solid wheels and tires of forged and rolled alloyed steel, quenched and tempered, for railroad traction vehicles and cars.
Solid wheels and tires for railroad vehicles have previously been made of steel containing 0.48 to 0.52% carbon and 0.75 to 0.80% manganese as determined in accordance with UIC Code 812-3/V, 5th edition, Jan. 1, 1984.
The most practical steel is steel R7. Its tensile strength (Rm) is 820 to 940 N/mm.sup.2, its break elongation (A.sub.5) at least 14%, and its notch-impact work at least 15 Nm in ISO U sections. All these levels are for 20.degree. C. (room temperature).
Steel R7 is preferably employed for block-braked solid wheels in cars with high axle loads.
From known wheel fractures and from the research into their etiologies conducted on specific steels it has been concluded that one cause of UIC-Code steel breakage is insufficient tenacity.
High-speed trains are also equipped with wheels of UIC Code 812-3/V Steel R7. More rigid specifications deriving from heavier axle loads, higher speeds, and greater braking forces, especially in conjunction with the constant braking that occurs in mountainous regions, can also lead to wheel fracture.